Phylogeography and support vector machine classification of colour variation in panther chameleons....
- Thread starter kinyonga
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Chris Anderson
Dr. House of Chameleons
Unfortunately the case with F. pardalis needing to be split into different species is far from clear cut, and there is not agreement on whether there is evidence yet to support doing so. With regard to the referenced paper, there was a lot more hype about the new species suggestion of this paper (particularly in the media) than the data behind it actually warranted, in my opinion. The authors did a good job of showing that there are population level genetic differences and limited gene flow between many of these geographic groups, as shown in the figures. They also showed limited, but consistent color variation differences between these populations. This has considerable implications on our understanding of how these forms have evolved and are continuing to evolve, and also has serious implications for the practice of locality hybridizing in captivity. I think they fell well short of justifying the need to split them all into different species, or even subspecies, however.
The reality is that there can be levels of genetic divergence between populations that will not justify species or subspecies level differentiation, but even where these delineations should be is fiercely debated among scientists. Taxonomy is an integrative science, and if and when these forms are described as independent species, more genetic data (e.g., a phylogeny), morphological data (e.g., differentiating features), and additional ecological data are going to be needed to justify such a split. The current genetic data definitely shows that there is genetic structure that warrants further examination, but ultimately additional study is still needed as far as the possibility of any taxonomic changes are concerned.
I do not mean to suggest that future work may not well provide the missing pieces needed to support this hypothesis. I simply hope to make clear that at this point I don't think the data conclusively supports it. I've long thoughts that the localities of this and many other species represented evolutionary steps in the process of becoming new species, but the question becomes how far along is this process are they and where do they transition from something like a genetically distinct population, to a subspecies (however controversial such a taxonomic level may be), or to a species? That is the question that still needs to be answered, and more data is needed in order to do so correctly.
Obviously, no one here was suggesting that these should be considered different species, but every time this paper comes up that idea seems to take off, so I try to make a point of clarifying what the data actually supports vs what the media took from it.
Chris
The reality is that there can be levels of genetic divergence between populations that will not justify species or subspecies level differentiation, but even where these delineations should be is fiercely debated among scientists. Taxonomy is an integrative science, and if and when these forms are described as independent species, more genetic data (e.g., a phylogeny), morphological data (e.g., differentiating features), and additional ecological data are going to be needed to justify such a split. The current genetic data definitely shows that there is genetic structure that warrants further examination, but ultimately additional study is still needed as far as the possibility of any taxonomic changes are concerned.
I do not mean to suggest that future work may not well provide the missing pieces needed to support this hypothesis. I simply hope to make clear that at this point I don't think the data conclusively supports it. I've long thoughts that the localities of this and many other species represented evolutionary steps in the process of becoming new species, but the question becomes how far along is this process are they and where do they transition from something like a genetically distinct population, to a subspecies (however controversial such a taxonomic level may be), or to a species? That is the question that still needs to be answered, and more data is needed in order to do so correctly.
Obviously, no one here was suggesting that these should be considered different species, but every time this paper comes up that idea seems to take off, so I try to make a point of clarifying what the data actually supports vs what the media took from it.
Chris
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